Portable hand-held electronic devices such as a Personal Data Assistant (PDA), a two-way pager or a two-way email-messaging device are becoming increasingly important. However, to improve portability and hence widespread usage of these devices, the size of these devices must be reduced. Due to current electronic technology, the thickness of hand-held electronic devices is at an acceptable level. However, device users would like to see a reduction in the width of these handheld devices. In fact some users would prefer a handheld device that resembles a cell phone in which the handheld device may be slightly increased in length but reduced in width.
The electronic components that are used to construct these handheld devices can facilitate a size reduction for virtually any dimension of the device. However, it is the conventional physical user interface, such as the display and the input devices (i.e. keyboard), which places a limitation on the reduction in the length and width of these devices. The display must be maintained at a certain size so that user interaction with the device is not degraded based on the functionality that the device is providing for the user (such as text messaging, web-surfing or game-playing). Accordingly, there is a need for an alternative configuration for the input device that will facilitate a reduction in size for the hand-held electronic device.
The main input device for hand-held electronic devices is a keyboard. Keyboards are typically laid out in the QWERTY fashion. QWERTY is a reference to the order of the keys starting with the left most key in the uppermost row of the keyboard. In the standard QWERTY keyboard layout, the letter keys are laid out in three rows with a minimum of seven letter keys per row. In addition, special function keys are usually provided for entering numerals, punctuation or for editing purposes (i.e. the spacebar key, the return key, the delete key, etc.). Foreign language keyboards follow a similar keyboard layout that is referred to as an AZERTY or QWERTZ format.
In order to reduce the size of the keyboard, one may reduce the number of letter keys by combing several letters on one key. Another option is to provide a key with more than one function. For instance, some keys can represent a letter and a number, or a letter and an editing feature. Another key can be depressed, such as an ALT key, to choose between the symbol or function that a given key provides. However, if not done properly, a reduction in the number of keys may reduce the usefulness of the input device. For instance, it may take longer for the user to interact with the handheld device which will lead to frustration on the part of the user. This is unacceptable since it is desirable to have a handheld device with a smaller keyboard that allows the user to maintain typing speed and accuracy. In addition, following a standard QWERTY layout in which the keys are provided in substantially horizontal rows still results in a handheld device in which the width of the device is not greatly reduced.
Another problem with the QWERTY layout is that the user will typically grip the handheld device such that their fingers support the handheld device and their thumbs are used for typing. Consequently, a variety of thumb movements are required in order to reach all of the keys on the keyboard. These thumb movements for conventional QWERTY keyboards generally involve a combination of multi-directional movements that are not naturally occurring movements of the thumbs. This will lead to premature user fatigue.
Accordingly, there is a need for handheld devices with a keyboard interface that is compact yet at the same time functional. The keys of the keyboard should be arranged to reduce the size of the keyboard interface while at the same time better reflecting the natural movements of the human thumb as well as maintaining functionality and ease of use.